Metal spraying apparatus

ABSTRACT

An apparatus for melting and spraying molten fusible metals and metal alloys. The metal spraying apparatus is portable and includes an insulated container having heaters installed therein preferably at the bottom for heating metal contained in the container to a molten state. A spray head is mounted on the container and has an inlet tube extending to adjacent the bottom of the container near the heater. An air supply is connected to the spray head and furnishes heated air under pressure through a venturi at the tube connection to siphon the molten metal from the container and carry it to a spraying nozzle. A second heater is in the spraying head to heat a portion of the air from the air supply to have the air blast in the spraying head at a temperature of or above the melting point of the metal. The air blast siphons molten metal, atomizes same and propels the molten metal through the nozzle onto surfaces for adhesion therewith in the form of a coating.

United States Patent [191 Payne, Jr.

Dec. 4, 1973 METAL SPRAYING APPARATUS Primary Examiner-M. Henson Wood,Jr.

. Assistant Examiner-Andres Kashnikow [76] Inventor: Paul H. Payne, Jr.,8512 Lee s Summit Rd, Kansas City Mo Attorney-Claude A. Flshbum et a].64139 22 Filed: Jan. 8, 1973 [571 ABSTRACT [21] AppL NOJ 321,652 Anapparatus for melting and spraying molten fusible metals and metalalloys. The metal spraymg apparatus a is portable and includes aninsulated container having 219/421, 222/146 HE, heaters installedtherein preferably at the bottom for 239/135 239/346, 239/365 heatingmetal contained in the container to a molten llll. Cltate A spray headis mounted on the container and of Search 81, 82, 85, has an inlet tubeextending to adjacent bottom of the container near the heater. An airsupply is con- 4245; 222/146 HE nected to the spray head and furnishesheated air under pressure through a venturi at the tube connec-References Cited tion to siphon the molten metal from the containerUNITED STATES PATENTS and carry it to a spraying nozzle. A second heateris in 1,792,551 2 1931 Rice et a1 239 135 the Spraying heed to heat aPortion of the air from, the 2,434,911 1/1948 Denyssen 239 79 x air pp yto have the air blast in the Spraying head at 2,068,205 1/1937 Steckel,Jr. et al. 239/133 a temperature of or above the melting point of the2,530,186 11/1950 Trimm et al. 239/82 metaL The, air blast siphonsmolten metal, atomizes 2,646,314 7/1953 239/296 same and propels themolten metal through the nozzle 2,795,461 6/1957 Durkm 222/146 HE X ontosurfaces for adhesion therewith in the form of a coating.

10 Claims, 4 Drawing Figures w fink;

2 69 57 45 9 I 62 59 5 was 43 4526") M 5 f 5| 75 29 i 1 i4 50 3" xr le/1 17:: IIIIIIZZI... k 5f Q zs x B 2 Q Q 9 22 5 I27 g PATENTED BEE 41975SHEET 1 UF 2 METAL SPRAYING APPARATUS The principal objects of thepresent invention are: to provide a portable spraying apparatus having acontainer with heating elements to melt fusible metal therein and aspraying head on the container and subjected to the action of hot airunder pressure to siphon molten metal from the container and atomize andpropel the atomized particles or droplets at a high velocity onto asurface to be coated; to provide such an apparatus wherein a heater isarranged to direct the heat to the metal container and particularly thebottom thereof to melt and maintain the metal molten with a siphon tubeinlet in the area of highest molten metal temperature; to provide suchan apparatus with a siphon and venturi wherein pressurized hot air isdirected through the venturi at high velocity to move molten metal fromthe container to the spraying head; to provide such an apparatus with aspraying head and nozzle with superheated air jets to maintain minuteparticles of atomized metal molten and aid in propelling same from thenozzle; to provide such an apparatus wherein the container and sprayinghead are provided with a handle or grip for manipulating same and aircontrols thereon for actuation by the operator; to provide such anapparatus with electric heaters as the heat source thereby eliminatingthe need for open flame heat sources; to provide such an apparatus withheat insulation for shielding the electric heaters and the containerwhereby the heat is concentrated in the container with a minimum of heatloss; to provide such an apparatus'with a hot air supply that is dividedinto separate flow streams, one to siphon the molten metal from thecontainer and the other flow stream having additional heat added theretoto atomize the siphoned molten metal whereby the hot air maintains thesiphoned metal in a molten state; to provide such an apparatus whereinthe heaters for melting the metal and for heating the air are separatewhereby the temperatures of each can be separately controlled; toprovide such a metal spraying apparatus with a seal for sealing thecontainer preventing accidental spillage therefrom; to provide such anapparatus with means to equalize the pressure in the container with thepressure outside the container thereby allowing siphoning of the moltenmetal from the container; and to provide such a metal spraying apparatusthat is suitable for its intended use, compact in construction, readilymanipulated by an operator, having a minimum number of parts, sturdy inconstruction and safe in operation.

Other objects and advantages of the present invention will becomeapparent from the following description taken in connection with theaccompanying drawings wherein are set forth by way of illustration andexample certain embodiments of this invention.

FIG. 1 is a perspective view of a metal spraying apparatus.

FIG. 2 is a plan view of the metal spraying apparatus.

FIG. 3 is a front elevational view of the metal spraying apparatus.

FIG. 4 is a side elevation view sectioned along the line 44 to showstructural details thereof.

Referring more in detail to the drawings:

As required, detailed embodiments of the present invention are disclosedherein. However, it is to be understood that the disclosed embodimentsare merely exemplary of the invention which may be embodied in variousforms. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting but merely as a basis forthe claims and as a representative basis for teaching one skilled in theart to variously employ the present invention in virtually anyappropriate detailed structure.

A metal spraying apparatus designated generally by the reference numeral1 uses hot air delivered to a spray head 2 to siphon molten metal alloyfrom a container 3 and propel same through a passage 5 to a sprayingnozzle 7. Air flows through a heater 9, and is super-heated and isthereafter directed into the spraying nozzle 7 and out spray orifices orjets 10 with high velocity to futher atomize the molten metal and topropel same onto a surface that is to be coated with the alloy.

In the illustrated structure the container 3 includes an elongate vessel1 1 having a bottom wall 12, side wall 13 and an open top 14 adapted tobe closed by a cover 15 which is part of the spray head 2. The vesselpreferably has an annular flange 16 at its upper end seating a seal ringor gasket 17 which is compressed between the cover 15 and flange 16 toseal the open top 14 and define a chamber 18 in the vessel 11 forcontaining metal to be melted and sprayed as later described. The vesselwalls are of a suitable metal to withstand heat and be inert to themetal or alloy to be melted, for example, stainless steel and the like.

The vessel 11 is suitably heated to melt the metal to be sprayed and isinsulated to hold the heat in the vessel and prevent heat loss. In thestructure illustrated one or more electric heaters 20 of an electricallyinsulated rod type are positioned in a receiver 21 formed of materialhaving high heat conductance and the receiver 21 is secured in heatconducting contact with the vessel wall for heating metal in the chamber18. The heater receiver 21 may be formed of copper and is of a size tocontact substantially the bottom wall 12. Heat insulation 22 surroundsthe vessel walls and the receiver 21 and is illustrated as a suitablelayer covering the sides 13 of the vessel 11 from the flange 16 andextending under the receiver 21. An outer shell 23 encloses theinsulation to hold same in place, said shell 23 having a bottom 24 andside wall 25 with the upper portion of said side wall 25 separated fromthe flange 16 by insulation as at 26 to prevent heat transfertherebetween. The shell 23 has suitable openings 27 for electricalconnection to the heater elements 20 as with a conductor 28 being shownas connected to said heater element 20 and extending to a suitablesource of electrical current.

The spray head 2 includes a container cover 15 which is removablymounted on the container 3 and when secured thereto closes the openupper end of the vessel 11. The cover 15 is held in place by suitablefastening structure and as illustrated said cover has a wall 29 with aperipheral flange 30 extending downwardly around the upper portion ofthe shell side wall 25. The flange 30 has a plurality ofcircumferentially spaced slots 31 therein to receive clamping bolts 32.The bolts are swingably mounted on the shell 23 by pins 33 in lower endsof the bolts and pivotally mounted in bearings 34 of cars 35 fixed tothe shell side wall 25 the bolts 32 have threaded upper portions 36 andclamping members such as wing nuts 37 are threaded on the bolts toengage the cover 15 and secure same on the container to close same andprevent accidental spilling of molten metal from the container.

A hand grip 39 is connected to the cover 15 and spray head 2 and extendsoutwardly and downwardly therefrom in spaced relation to the containershell 23. The hand grip 39 providing means for manipulating the sprayingapparatus. Preferably, the hand grip 39 is made of a material having lowheat conductance or can have a layer of insulation (not shown)therearound.

The spray head 2 includes a tubular member 43 secured to a mountingmember 44 that preferably is integral with the cover 15 extendingupwardly therefrom. The tubular member 43 has the hand grip 39 securedthereto in any suitable manner wherein a flow passage (not shown)extending through the hand grip 39 opens into the interior of thetubular member 43. A venturi 45 is suitably secured to the tubularmember 43 such as by threaded engagement and extends between the tubularmember 43 and a second tubular member 46, that defines the dischargepassage 5, forming a flow passage therebetween. The venturi 45 has asmall orifree 47 opening into the second tubular member 46 and directedtoward an open end thereof. Preferably, the discharge tube member 46 isencased in a receiver 48, that is made of a material having high heatconductance, and has the venturi 45 in threaded engagement therewith forsecuring the discharge tube member 46 to the venturi 45. As illustrated,the exposed portions of the venturi 45 between the tube members 46 and43 are surrounded by insulation 49 secured thereto.

A siphoning or induction tube 50 extends through the cover 15 having thelower end thereof adjacent the bottom wall 12 of the vessel 11 and anupper end extending through the receiver 48 and discharge tube 46 intothe interior of the discharge tube 46 adjacent to the orifice 47 in aninduction area. The upper end 51 of the siphoning tube 50 preferably iscut diagonally with the edge adjacent the venturi 45 being higher havingthe diagonal end sloping downwardly therefrom. The siphoning tube 50 canbe held in position by any suitable means such as a set screw 52 that isin threaded engagement with the receiver 48.

A conduit 54 is secured to the tubular member 43 extending upwardlytherefrom and opening into the interior thereof between the hand grip 39and the venturi 45. Preferably, the conduit 54 has a bend thereinwherein the conduit extends above the receiver 48 to the spraying nozzle7 to which it is suitably connected to form an air flow path from thetubular member 43. As illustrated, the conduit 54 has an end 55 that isY- shaped dividing it into two air flow passages each communicating withan annular flow passage 57 in the spray nozzle 7 preferably on oppositesides thereof. The spray orifices 10 open into the annular flow passage57 and are directed at an angle relative to the iongitudinal axis of thetube 46 for a purpose later described. The spray nozzle 7 has an opening58 therethrough with the discharge passage directed axiallytherethrough, the opening 58 being partially defined by a chamferedsurface portion 59. The spray orifices are spaced circumferentiallyabout the opening 58 and open onto the surface 59 and are directed awayfrom the spraying nozzle 7 toward a point spaced in front of thespraying nozzle 7 in line with the axis of the discharge passage 5.Preferably, both the conduit 54 and the tubular member 43 haveinsulation 61 and 62 respectively covering the exposed surfaces thereof.

The conduit 54 is suitably heated by the heater 9 and extends through anupper portion 64 of the receiver 48 that preferably has insulation 65therearound to prevent heat loss. The heater 9 includes heating elements66 that are mounted in the upper portion 64 around the conduit 54 andare operable for supplying heat thereto. As illustrated, the heatingelements are electrically insulated rod type heaters having a conductor67 for electrical connection. It is to be noted that other types ofelectrical heaters can be used to supply heat to air that flows throughthe conduit 54. Spacing leg members 69 extend between and connect theupper portion 64 to the remainder of the receiver 48 and are operable totransfer heat from the upper portion 64 to the tube 46.

Air from a pressurized source is supplied to the spraying apparatus 1through a flexible conduit 71 after flowing through a suitable airheater 72. As illustrated, the conduit 71 is connected to the hand grip39 to flow through the flow passage therein and into the tubular member43. A suitable valve (not shown) is mounted in the hand grip 39 forcontrolling the flow of hot air therethrough, the valve being actuatedby a lever 73 that is pivotally mounted on the hand grip 39. The hot airflows through the tubular member 43 into the venturi 45 and the conduit54. The hot air flowing through the conduit 54 is further heated orsuper-heated by the heater 9 preferably to a temperature above themelting point of the metal to be sprayed, this requires that heaters 66heat the conduit 54 to a very high temperature to supply adequate heatto the air flowing therethrough.

The present invention is more fully understood by description of theoperation thereof. The container 3 is removed from the cover 15 andeither solid metal or molten metal is placed therein. If solid metal isused, it would first be heated to a molten state before the container 3is secured to the cover 15. Having the metal or metal alloy moltenpermits the siphoning tube 50 to enter the container 3 with a minimum ofresistance and preferably the bottom of the siphoning tube 50 ispositioned adjacent to the bottom wall 12 of the vessel 11 so as to bein the hottest part of the molten metal. The heaters 20, 66 and 72 canbe connected to suitable temperature control means such as rheostats andshould be at the desired operating temperature before operation of thespraying apparatus 1. With the heaters 20, 66 and 72 at operatingtemperature, the operator grasps the handle 39 to hold the sprayingapparatus 1. He then directs the spraying apparatus 1 at the surface tobe coated with the molten metal or metal alloy and by depressing thelever 73 air flows through the handle 39 into the tubular member 43 andthe venturi 45. The air flowing through the venturi 45 has an increasein velocity by flowing through the orifice 47 and is directed over theend 51 of the siphon tube 50. Because the end 51 is cut diagonally andpositioned as described above, a negative pressure is created by the airflowing thereover thereby siphoning the molten metal or metal alloy fromcontainer 3 and into the discharge passage 5 wherein the air carries astream of the molten metal in the shape of small particles or dropsthrough the heated discharge passage 5 toward the spraying nozzle 7.Preferably, the tube 46 is of a material that the molten metal or metalalloy will not adhere thereto. Upon siphoning of the metal from thecontainer 3 the pressure therein would be reduced sufficiently so thatno more metal could be siphoned therefrom. A pressure equalizing port 75is provided in the cover 15 so that the pressure inside the vessel 11 issubstantially equal to the atmospheric pressure. The port 75 alsoprevents excessive pressure buildup in the vessel 11 reducing thepossibility of it exploding. It is to be noted that a suitable valvecould be installed in the port 75 to prevent flow of molten metaltherethrough if the spraying apparatus 1 were accidentally turned over.When the molten metal reaches the spraying nozzle 7, the heated airflowing through the conduit 54 and the spray orifices is of a sufficientflow rate and velocity to further atomize the stream of molten metal byimpinging on same. With the spray orifices 10 directed as describedabove, the air flowing through the spray orifices l0 and the venturi 45will propel the atomized molten metal toward the surface to be sprayed.The use of heated air is desired so that the molten metal will notsolidify before it reaches the surface to be coated. The heating of thetube 46 by the heaters 66 also prevents the molten metal fromsolidifying on the walls thereof. The spraying apparatus 1 isparticularly applicable for use with metals that have low meltingtemperatures such as lead and lead alloys and in particularly applicablefor spraying such alloys onto vehicle surfaces such as fenders that havebeen damaged.

It is to be understood that while I have illustrated and describedcertain forms of my invention, it is not to be limited to the specificform or arrangement of parts shown and described herein.

What I claim and desire to secure by Letters Patent l. A molten metalspraying apparatus comprising:

a. a container having an insulated vessel therein forming a chamber toreceive metal material to be reduced to a molten state;

b. a heater in said container in heat transfer relation to lower part ofsaid vessel and operative to melt said material and maintain same in amolten state;

0. a spray head having an induction area with a discharge passage;

d. an induction tube on said spray head and extending from an open endin said induction area to adjacent the bottom of the vessel chamber andcommunicating said chamber with said induction area;

e. an air duct connected to a hot air supply and having a control forselective delivery of hot air under pressure to the spray head;

f. a venturi member in said spray head receiving said hot air anddirecting same at high velocity across said tube open end in theinduction area to siphon molten material from said chamber and propelsame in a stream of dispensed particles through said discharge passage;

g. means directing a plurality of high velocity jets of air having atemperature above the melting point of said metal material in impingingrelation into said stream of dispensed particles to atomize and heatsame whereby the material is discharged in a spray of atomized moltenmaterial.

2. A molten metal spraying apparatus as set forth in claim 1 whereinsaid air jet directing means includes:

a. a spray nozzle having an opening aligned with said discharge passagefor discharge of said molten material particles therethrough;

b. a second air passage in the spray head and connected to said hot airsupply;

0. heating means operative to heat air in said second passage.

3. A molten metal spraying apparatus as set forth in claim 2 wherein:

a. said spray nozzle has an annular member with an annular passagetherein connected to said second passage to receive hot air therefrom;

b. said annular member has a plurality of circumferentially spaced jetapertures communicating with said annular passage and angled inwardlyand toward the direction of spray discharge whereby jets of hot airintersect the stream of dispensed particles from the discharge passage.

4. A molten metal spraying apparatus as set forth in claim 1 andincluding:

a hand grip;

b. means connecting said hand grip to the spray head to support same andthe container therefrom;

c. said air duct extending through said hand grip;

d. said control is a valve in the hand grip and a pivoted leverextending therefrom for operation by the hand of a person holding thehand grip.

5. A molten metal spraying apparatus as set forth in claim 1 wherein:

a. said heater in the container is a receiver of high thermalconductivity having a surface in heat transfer contact withsubstantially all of a bottom wall of the vessel, an electricallyinsulated electric heating element in said receiver and connected to asource of electrical energy to heat the bottom of the vessel and meltmetal material in said vessel;

b. said induction tube having an open lower end adjacent said vesselbottom wall where the molten material has the highest temperature.

6. A molten metal spraying apparatus as set forth in claim 5 wherein:

a. said spray head has a portion with the induction area and dischargepassage therein and is of a material having high heat conductivity;

b. said high velocity air jet directing means having air passage meansconnected to said air duct and receiving air under pressure therefrom;

c. a second heater means in heat transfer contact to said air passagemeans and operative to heat air passing therethrough to a temperatureabove the melting point of said metal material;

d. said second heater means and air passage means being in heatconductive relation to said spray head portion to heat same and thedischarge passage therein.

7. A molten metal spraying apparatus as set forth in claim 6 wherein:

a. a spray nozzle having an opening aligned with said discharge passagefor discharge of said molten material particles therethrough;

b. a second air passage in the spray head and connected to said hot airsupply;

0. heating means operative to heat air in said second passage.

8. A molten metal spraying apparatus as set forth in claim 7 andincluding:

a hand grip;

b. means connecting said hand grip to the spray head to support same andthe container therefrom;

c. said air duct extending through said hand grip;

d. said control is a valve in the hand grip and a pivoted leverextending therefrom for operation by the hand of a person holding thehand grip.

9. A molten metal spraying apparatus as set forth in claim 8 wherein:

a. said spray nozzle has an annular member with an annular passagetherein connected to said second passage to receive hot air therefrom;

b. said annular member has a plurality of circumferentially spaced jetapertures communicating with said annular passage and angled inwardlyand toward the direction of spray discharge whereby jets of hot airintersect the stream of dispensed particles from the discharge passage.

10. A molten metal spraying apparatus comprising:

a. a container having an insulated chamber therein for receiving metalmaterial to be melted;

b. means heating said metal material and maintaining same melted in thechamber;

0. spray head having a connection to a source of high pressure hot airand a discharge passage and a venturi directing said hot air in a highvelocity stream into said passage;

d. means effecting flow of molten material from said a second heaterassociated with said spray head to heat same;

. means directing hot air in heat transfer relation to said secondheater and jetting same into the molten metal directed from saiddischarge passage to atomize same, said jetted air being of atemperature above the melting point of said metal material.

1. A molten metal spraying apparatus comprising: a. a container havingan insulated vessel therein forming a chamber to receive metal materialto be reduced to a molten state; b. a heater in said container in heattransfer relation to lower part of said vessel and operative to meltsaid material and maintain same in a molten state; c. a spray headhaving an induction area with a discharge passage; d. an induction tubeon said spray head and extending from an open end in said induction areato adjacent the bottom of the vessel chamber and communicating saidchamber with said induction area; e. an air duct connected to a hot airsupply and having a control for selective delivery of hot air underpressure to the spray head; f. a venturi member in said spray headreceiving said hot air and directing same at high velocity across saidtube open end in the induction area to siphon molten material from saidchamber and propel same in a stream of dispensed particles through saiddischarge passage; g. means directing a plurality of high velocity jetsof air having a temperature above the melting point of said metalmaterial in impinging relation into said stream of dispensed particlesto atomize and heat same whereby the material is discharged in a sprayof atomized molten material.
 2. A molten metal spraying apparatus as setforth in claim 1 wherein said air jet directing means includes: a. aspray nozzle having an opening aligned with said discharge passage fordischarge of said molten material particles therethrough; b. a secondair passage in the spray head and connected to said hot air supply; c.heating means operative to heat air in said second passage.
 3. A moltenmetal spraying apparatus as set forth in claim 2 wherein: a. said spraynozzle has an annular member with an annular passage therein connectedto said second passage to receive hot air therefrom; b. said annularmember has a plurality of circumferentially spaced jet aperturescommunicating with said annular passage and angled inwardly and towardthe direction of spray discharge whereby jets of hot air intersect thestream of dispensed particles from the discharge passage.
 4. A moltenmetal spraying apparatus as set forth in claim 1 and including: a handgrip; b. means connecting said hand grip to the spray head to supportsame and the container therefrom; c. said air duct extending throughsaid hand grip; d. said control is a valve in the hand grip and apivoted lever extending therefrom for operation by the hand of a personholding the hand grip.
 5. A molten metal spraying apparatus as set forthin claim 1 wherein: a. said heater in the container is a receiver ofhigh thermal conductivity having a surface in heat transfer contact withsubstantiaLly all of a bottom wall of the vessel, an electricallyinsulated electric heating element in said receiver and connected to asource of electrical energy to heat the bottom of the vessel and meltmetal material in said vessel; b. said induction tube having an openlower end adjacent said vessel bottom wall where the molten material hasthe highest temperature.
 6. A molten metal spraying apparatus as setforth in claim 5 wherein: a. said spray head has a portion with theinduction area and discharge passage therein and is of a material havinghigh heat conductivity; b. said high velocity air jet directing meanshaving air passage means connected to said air duct and receiving airunder pressure therefrom; c. a second heater means in heat transfercontact to said air passage means and operative to heat air passingtherethrough to a temperature above the melting point of said metalmaterial; d. said second heater means and air passage means being inheat conductive relation to said spray head portion to heat same and thedischarge passage therein.
 7. A molten metal spraying apparatus as setforth in claim 6 wherein: a. a spray nozzle having an opening alignedwith said discharge passage for discharge of said molten materialparticles therethrough; b. a second air passage in the spray head andconnected to said hot air supply; c. heating means operative to heat airin said second passage.
 8. A molten metal spraying apparatus as setforth in claim 7 and including: a hand grip; b. means connecting saidhand grip to the spray head to support same and the container therefrom;c. said air duct extending through said hand grip; d. said control is avalve in the hand grip and a pivoted lever extending therefrom foroperation by the hand of a person holding the hand grip.
 9. A moltenmetal spraying apparatus as set forth in claim 8 wherein: a. said spraynozzle has an annular member with an annular passage therein connectedto said second passage to receive hot air therefrom; b. said annularmember has a plurality of circumferentially spaced jet aperturescommunicating with said annular passage and angled inwardly and towardthe direction of spray discharge whereby jets of hot air intersect thestream of dispensed particles from the discharge passage.
 10. A moltenmetal spraying apparatus comprising: a. a container having an insulatedchamber therein for receiving metal material to be melted; b. meansheating said metal material and maintaining same melted in the chamber;c. spray head having a connection to a source of high pressure hot airand a discharge passage and a venturi directing said hot air in a highvelocity stream into said passage; d. means effecting flow of moltenmaterial from said chamber to said discharge passage in resonse to saidhigh velocity air stream, said air stream dispensing the molten materialin minute particles and discharging same from said passage; e. a secondheater associated with said spray head to heat same; f. means directinghot air in heat transfer relation to said second heater and jetting sameinto the molten metal directed from said discharge passage to atomizesame, said jetted air being of a temperature above the melting point ofsaid metal material.